1. Field of the Invention
The subject invention generally relates to a seat for a vehicle, and more specifically to the seat having at least one energy absorbing feature.
2. Description of the Related Art
Seats for a vehicle and specifically a back portion of the seat typically must meet structural requirements by having sufficient strength to support repeated loads, which are exerted on the back portion of the seat, or seat back, during a crash event. For example, when a vehicle is hit from behind by another vehicle, a mass of an occupant applies a large force on the seat back over a small time period. To meet these structural requirements, the seat back is generally formed from metal such as steel, aluminum, or magnesium. For example, the seat back made from steel is able to meet the structural requirements by providing sufficient stiffness, strength, and ductility to satisfy the above-mentioned requirements.
Recently, more features and content have been designed into the seat back. As a result, a cost to manufacture the seat back has increased. In order to reduce costs, seat backs previously manufactured from metals are now being manufactured from a polymeric material. The seat backs produced from the polymeric material offer the ability to reduce the number of features and content designed into the seat back and therefore reduce manufacturing and assembly costs. Furthermore, weight reduction is another possible benefit of using polymeric material for the seat back, as well as greater design freedom and reduced profile, giving the vehicle increased interior space. However, the seat back made from the polymeric material must still meet the structural requirements for a crash event. For example, during a rear impact collision, the vehicle is accelerated in a forward direction. This causes the seat back to apply acceleration forces to the occupant over a short period of time. Therefore, the seat backs are typically required to manage the acceleration forces applied to the occupant while not exceeding deformation limits.
A seat supports an occupant of a vehicle. The seat comprises a seating frame member for providing a surface to support the occupant. The seat also comprises a back frame member extending away from the seating frame member. The back frame member defines a U-shaped cavity. The back frame member has a base portion and two or more leg portions extending from the base portion to define the U-shaped cavity. The seat includes a bracket coupled to both the seating frame member and the back frame member. A boss is coupled to the base portion within the U-shaped cavity. A bore is defined by and extends axially through the boss. A fastening element is received by the bore and extends through the boss, the base portion, and the bracket for coupling the bracket to the back frame member. The fastening element deforms the boss and the base portion when a force above a predetermined value is applied to the back frame member thereby causing the back frame member to rotate relative to the seating frame member. Allowing the back frame member to rotate relative to the seating frame member reduces an impact force transferred from the seat to the occupant caused by the force above the predetermined value. Therefore, the back frame member can be designed to withstand forces up to the predetermined value to ensure it remains intact during the collision event. Reducing the impact force experienced by the occupant reduces the likelihood of the occupant sustaining injuries as a result of a collision of the vehicle.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description, when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numeral indicate like or corresponding parts throughout the several views, a seat 30 for a vehicle is generally shown. The seat 30 is coupled to the vehicle for supporting an occupant 32 in a standard position within the vehicle. With reference to
The back frame member 36 generally extends vertically away from the seating frame member 34. The back frame member 36 may include a first side member 40 and a second side member 42 each extending generally upwardly from the seating frame member 34. The side members 40, 42 each have a proximal end 44 proximate the seating frame member 34 and a distal end 46 spaced from the seating frame member 34. With reference to
The back frame member 36 may comprise a polymeric material. The polymeric material is typically a thermoplastic material for allowing the side members 40, 42 to be injection molded. For example, the polymeric material of the side members 40, 42 may comprise a polyamide. When employed, the polyamide is selected from the group of nylon 6, nylon 6/6 and combinations thereof. The polyamide may be a fiber reinforced polyamide. An example of a suitable fiber reinforced polyamide is a glass-fiber reinforced polyamide that is commercially available from BASF Corporation under the trade name Ultramid® TG7S PA6. It should be appreciated that the side members 40, 42 may be formed from any type of suitable polymeric material, polyamide or not, reinforced or not, without departing from the nature of the present invention.
As best shown in
Typically, the reinforcing mat 52 comprises a glass-fiber filled polymeric material. It is to be appreciated that the glass-filled polymeric material may be the polymeric material of the back frame member 36 described above. Alternatively, the glass-filled polymeric material may be different from the polymeric material of the back frame member 36. Generally, glass fibers within the glass-filled polymeric material extend along the longitudinal axis 56 of the reinforcing mat 52. However, the plurality of fibers may extend in different directions or may be woven, i.e., interlaced with each other. Typically, the glass fibers are elongated such that stress on the reinforcing mat 52 is transmitted from the glass-filled polymeric material to the glass fibers. Transferring the stress allows the glass fibers to reinforce the glass-filled polymeric material.
The glass-filled polymeric material of the reinforcing mat 52 may be integrated with the glass fibers in a variety of ways. For example, the reinforcing mat 52 may be in the form of a continuous fiber reinforced mat that is preformed and subsequently integrated with the glass-filled polymeric material. An example of a suitable continuous fiber reinforced mat is that which is commercially available from Performance Materials Corporation of Camarillo, Calif. under the trade name Continuous Fiber Reinforced Thermoplastic (CFRT).
With reference to
As best shown in
With reference to
The boss 68 defines a bore 70 extending axially through the boss 68. The base portion 60 defines an upper fastening hole aligned with the bore 70 of the boss 68. A fastening element 72 is received by the bore 70 of the boss 68. The fastening element 72 extends through the boss 68, the upper fastening hole of the base portion 60, and the bracket 38 for coupling the bracket 38 to the back frame member 36. The fastening element 72 has a cylindrical shaft 74 in contact with the boss 68. As shown in
Generally, during a collision event, such as a rear end collision, the occupant 32 sitting in the seat 30 is impacted by the back frame member 36 of the seat 30 as the vehicle is abruptly accelerated forward. As a result, the occupant 32 applies a collision force to the seat 30 and conversely, the seat 30 applies an impact force, which is related to the collision force, to the occupant 32. However, the impact force can be reduced compared to the collision force by providing an energy absorbing feature to dissipate a portion of the collision force. As shown in
The boss 68 is the energy absorbing feature and deforms as the occupant 32 applies the collision force to the back frame member 36. Specifically, as shown in
The rotation of the back frame member 36 reduces the impact force transferred from the seat 30 to the occupant 32 caused by the force above the predetermined value. Generally, the fastening element 72 deforms the boss 68, the base portion 60, and, if present, the reinforcing mat 52 when the force above the predetermined value is applied to the back frame member 36. When the sleeve 76 is present, the fastening element 72 contacts the sleeve 76 and the sleeve 76 deforms the boss 68 when the force above the predetermined value is applied to the back frame member 36.
Generally, the deformation of the boss 68 continues until the collision force is entirely dissipated or the boss 68 ruptures. The cylindrical shaft 74 of the fastening element 72 contacts the boss 68 to rupture the boss 68. Once the boss 68 is ruptured, the back frame member 36 continues to rotate relative to the seating frame member 34 and the cylindrical shaft 74 of the boss 68 shears through the base portion 60 of the back frame member 36 and, if present, the reinforcing mat 52. Generally, the shearing of the base of the back frame member 36 and the reinforcing mat 52 continues until the collision force is entirely dissipated or the fastening element 72 contacts one of the leg portions 62 of the back frame member 36. Because the fastening element 72 is designed to shear through the base portion 60 of the back frame member 36, the seat 30 is free of a shear plate, which must be separately added to the seat 30.
The deformation of the boss 68 and the shearing of the base portion 60 of the back frame member 36 results in a displacement of the occupant 32 from the standard position toward the back frame member 36 of the seat 30, as shown in
The stiffness of the boss 68 is dependent on the cross-sectional thickness of the boss 68. As shown in
As shown in
The boss 68 may comprise any suitable material meeting the stiffness requirements necessary to resist the normal loads applied to the back frame member 36. The boss 68 may comprise a polymeric material. It is to be appreciated that the polymeric material of the boss 68 may be the same as the polymeric material of the back frame member 36. As such, the boss 68 may be integrally formed with the back frame member 36. Alternatively, the polymeric material of the boss 68 may be different from the polymeric material of the back frame member 36. Typically, the polymeric material of the boss 68 is selected from the group of nylon 6, nylon 6/6, and combinations thereof.
As shown in
It is to be appreciated that the boss 68 may be further defined, as an upper boss 68A and the seat 30 may further comprise a lower boss 68B spaced from the upper boss 68A. The lower boss 68B is coupled to the base portion 60 within the U-shaped cavity 58 similar to the upper boss 68A. When the lower boss 68B is present, the base portion 60 defines a lower fastening hole aligned with the bore 70 of the lower boss 68B. The lower boss 68B receives another fastening element 72 such that the fastening elements 72 are disposed through a respective one of the upper boss 68A and the lower boss 68B for coupling the bracket 38 to the back frame member 36. When the lower boss 68B is present, the back frame member 36 rotates about the lower boss 68B as the upper boss 68A is deformed by the fastening element 72. More specifically, the bracket 38 maintains a position of the fastening elements 72 relative to each other and relative to the seating frame member 34 as the back frame member 36 rotates relative to the seating frame member 34. Therefore, the back frame member 36 rotates about the fastening element 72 received by the lower boss 68B and the fastening element 72 received by the upper boss 68A deforms the upper boss 68A and the base portion 60 of the back frame member 36.
The seat 30 may include other energy absorbing features. For example, as shown in
As shown in
During the collision event, the cross member 74 deforms under the collision force applied by the occupant 32. Specifically, the cross member 74 is stretched resulting in a necking of the cross member 74. The deformation of the cross member 74 results in the displacement of the occupant 32 from the standard position toward the back frame member 36 of the seat 30. As stated above, the greater the displacement of the occupant 32 the greater the reduction of the impact force as compared to the collision force. Furthermore, the bracket 38 may be the energy absorbing feature and designed to deform as the back frame member 36 rotates relative to the seating frame member 34. Additional description of the bracket 38 used as the energy absorbing feature is disclosed in co-pending application Ser. No. ______ (Howard and Howard Docket No. 065322.00117) the contents of which are incorporated by reference.
Generally, the impact force experienced by the occupant 32 as a result of the collision force can be minimized with the energy absorbing feature while still satisfying safe displacement requirements for the back frame member 36 of the seat 30. With the energy absorbing feature, the impact force is managed over a longer time period, thereby reducing a peak impact force acting on the occupant 32. With the reduction of the peak impact force, the occupant 32 experiences less injury and the seat 30 also experiences lower stress levels. As a result of the seat 30 experiencing lower stress levels, more optimal designs can be utilized, and the polymeric materials can be used to manage the collision force.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The foregoing invention has been described in accordance with the relevant legal standards; thus, the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of the invention.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/382,582 filed on Sep. 14, 2010 and incorporated herewith in its entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US11/51571 | 9/14/2011 | WO | 00 | 3/13/2013 |
Number | Date | Country | |
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61382582 | Sep 2010 | US |